JPH0318628A - Acceleration control device for gas turbine engine - Google Patents

Abstract

PURPOSE: To determine an adequate stall margin by making the ratio of burner pressure and a prescribed engine internal pressure as a function for a reference value relating to a compressor rotor speed, and by controlling the burner pressure by this ratio and the actual burner pressure. CONSTITUTION: A function generator 32 outputs a stall limit signal PB/PS13.2 as a reference value previously determined as a function of speed signal N2 /θ<1/2> in correspondence to a prescribed engine station 13.2 within a bypass duct 15, and this is calculated by an arithmetic unit 44 as a limiting value of burner pressure PB for acceleration being the product of the actual value. The limiting valve of calculated PB and the actual value of burner pressure PB in an annular burner 20 are compared in a comparator 42, and on the basis of this error signal, a fuel controller 30 controls the fuel flow quantity to be supplied to the burner 20. Thus, the determination of the stall margin independent of compressor bleed, power extraction, degradation of engine efficiency or the like can be enabled.

Description

Detailed Description of the Invention [Field of Industrial Application] This invention relates to a gas turbine engine for powering an aircraft, and in particular to a gas turbine engine that can control the fuel supply to an appropriate value during acceleration. The present invention relates to an acceleration control device for a turbine engine.

[Prior Art] As is well known, gas turbine engines using axial flow compressors suffer from stalls and surges.
E) is easy to receive. Stalls are likely to occur in compressors when the angle of attack and other conditions cause the boundary layer of air adjacent to the compressor blades to separate, inducing FE force pulsations. If the pulsations do not subside and are allowed to propagate to other blades, the entire compressor may surge, leading to engine malfunction. Therefore, in this field, attempts have been made to provide means for removing the generated surge or preventing the generated surge from continuing, and further attempts have been made to provide means for preventing the surge.

Traditionally, fuel control systems are designed to provide a slip-open lube schedule with sufficient surge margin (f) to ensure that the engine is accelerated without generating surges.The permissible principles for such a schedule are The purpose is to provide a sufficient margin between the engine operating line and the surge line under worst-case operating conditions so that surges are avoided no matter what the engine conditions are.

The margin established using this principle is a compromise between the acceleration rate that can be achieved under the safest operating conditions and the surge margin required for the worst-case operating conditions.

Because acceleration time is always sacrificed to avoid surges, acceleration time is not as fast as desired under all but the worst driving conditions. Of course, it is ideal to accelerate the engine as quickly as possible, and so a means of ensuring the avoidance of surge while allowing rapid acceleration under all operating conditions is a desired goal in this art.

The surge margin required during acceleration is usually set based on the most severe (even if extremely unlikely) operating condition with PL that the engine may encounter, so it is based on the worst-case engine operating condition. It is clear that acceleration efficiency can be improved under most operating conditions if control is performed without assuming a surge margin. However, this is an unacceptable solution to the problem since surges must be avoided in all operating conditions to ensure flight safety.

As is known, the assignee of this application, United
JFC-1 manufactured by Hamill Technologies Corporation's Standard Division
Fuel control systems such as the 2, Jr.'C-60 and J FC-68 provide an open lube schedule with sufficient stall margin to avoid stall in all intended operations of the engine. For details of the acceleration control device, reference should be made to the control model described above.

Such a control system uses the control parameter Wf/PI3, where Wf is the fuel flow in bonds/time and PI3 is the burner pressure in bonds/ft absolute units. This parameter varies as a function of the twin spool engine's compressor speed (low pressure compressor N. or high pressure compressor N.) and other engine parameters selected to correct the compressor speed to the twin spool engine. is multiplied by the actual value of the burner pressure (1)B) or an equivalent parameter, thereby determining the fuel supply to the engine during acceleration.

In other engine control mechanisms (W r / P I
3 parameters and d which functions as a control parameter of the same temple.
tN+ or dtN, (speed change skewer signal) can be used. However, in any case, or combination thereof, the stall margin under conditions other than worst-case driving conditions must be excessive, and therefore the acceleration is inherently slower when not operating under worst-case conditions. Propose time. I will do it. These shortcomings of these devices are further accentuated when engine operating conditions deviate from standard conditions due to power extraction, compressor bleed, reduced engine efficiency, and the like.

``Problem to be Solved by the Invention 1 Therefore, it is an object of the present invention to provide a gas turbine capable of setting an appropriate stall margin in the entire operating range of the engine, independent of compressor bleed, power extraction, reduction in engine efficiency, etc. The purpose of the present invention is to provide an acceleration control device for an engine.

[Means and operations for solving the problems] In order to achieve objects other than 1; and 12, according to the first configuration of the present invention, 1" [compressor, generating engine working fluid a burner for accelerating the gas turbine engine; a turbine driven by the engine working fluid to drive the compressor; and fuel control means for controlling the fuel flow thI1 supplied to the burner depending on engine operating parameters. An acceleration control device for controlling a mode, comprising means for setting a stall margin of the compressor, the means controlling the pressure of the burner and other factors of the engine depending on the speed of the compressor. means for generating a first signal indicative of a compressor stall limit value as a reference value which is a ratio of the pressure at a given position 1d; and generating a second signal tp in response to the actual value of the pressure in the burner +iff; and means for controlling the fuel control means to limit the fuel flow M supplied to the burner in response to the i-th and second signals, the stall margin being a compressor bleed, An acceleration control system for a gas turbine engine is provided that is independent of power extraction and engine efficiency reduction.

According to a second configuration of the present invention, a compressor, a burner for generating engine working fluid, a turbine driven by the engine working fluid to drive the compressor, a fan, and the fan. an acceleration control device for controlling the acceleration mode of the gas turbine engine; 1) means for setting a stall margin of the compressor as described in item 4 above, the means being configured to adjust the pressure of the burner and the pressure at another predetermined position of the engine depending on the speed of the compressor; means for generating a first signal indicative of an rE compressor stall limit value as a reference value which is the ratio of if and means for generating a second signal in response to the actual value of the burner pressure; means for controlling the fuel control means to limit the fuel flow m supplied to the burner in response to a second signal; and means for compensating for pressure losses in the bypass duct; a function generator, the pressure loss compensation means producing a third signal indicative of the engine pressure ratio as a function of the speed of the compressor; and comparison means for generating a signal and correcting the first signal thereby.

[Embodiment] In the east embodiment, a twin spool type axial flow gas turbine fan jet 51 (a commercial engine is described, but the acceleration control equipment according to the present invention is applied to a straight jet used for non-military purposes). (Although shown in analog logic form in the examples, l) ET.'.C
F − known as (digital electronic engine system a)
100 series engine and F A D E C (
It can be used in electronic digital control systems such as those used in improved engines of the F-119 series, known as electronic digital control systems. .

F! The 00 series military engines are manufactured by the applicant, United Technologies Corporation! By a division of Blatt & Whitney Aircraft? The F119 is currently being developed for future military use.

In FIG. 1, a twin spool axial fan jet engine 10 includes a fan/low pressure compressor section l2 driven by a low pressure turbine section 14 (f) a low pressure spool and a high pressure compressor section driven by a high pressure turbine section l8. The annular burner 20 is supplied with fuel, and this fuel is combusted with pressurized air introduced into the burner 20 to generate high-temperature gas and power the turbine.Fan l2 The air introduced from is split by a splitter I3 so that part of it enters the core engine and the other part is bypassed through a bypass duct 15 to mix with the combustion gases from the core engine (turbine). Ru.

As is clear from Section 117i, the combustion gases emitted from the turbine (core engine) along with the emitted air from the bypass duct are ultimately ejected through the exhaust nozzle which provides thrust to the engine. In some other applications, an augmentor is used as disclosed in this preferred embodiment. Augmentor 24 adds additional thrust to the engine by burning fuel in the secondary combustor section. In this case,
The augmentor includes appropriate fuel nozzles, flame holders and exhaust nozzles 26. The passage cross-sectional area of the exhaust nozzle 26 is variably controlled so that an appropriate engine thermodynamic cycle is properly maintained when the augmentor is operating and when the augmentor is not operating. The fuel flow Jit supplied to the burner is automatically controlled to the Mii value by the fuel control device 30 according to the position of the power lever 27 so as to maintain the engine operating state optimally in the steady operating state and transient operating state of the engine. be done. In addition, the fuel control device 30 [
There may be any available conventional control system which may be implemented electronically, mechanically, hydraulically, hydromechanically or a combination thereof. In these conventional control devices, the speed that can be utilized by the present invention,
Temperature, pressure, etc. are used as control parameters.

As best schematically illustrated in FIG. 1, the acceleration control of the present invention produces a corrected velocity signal (N t/r o ). This speed signal is determined by the sea surface temperature value (518.7° Rankine temperature) and the compressor inlet temperature ('r,.s (the designation may vary depending on different engine systems and models) to find 0, and by dividing the rotational speed of the high pressure compressor, N, by the square root of this O. The compressor inlet temperature used in this calculation may be a directly detected value or a pile calculated from other detected values.
good. This speed signal (N., #0) is input to the function generator 32. The function generator 32 generates a stall limit signal (I'll/PS,
3,, ) on line 40.

This number 13.2 designates a predetermined engine station in the bypass duct 15, in this example downstream of the fan 12 and on the fourth side of the inlet of the vent. In addition, the pressure at other stations (
Pt. s. Pus. P@ etc.) can also be used. P R / P S I3. t is an approximate value of the pressure ratio of high pressure compressor 6. Immediately, the pressure in the bypass duct (line 36) is transferred via the bypass duct 15 to the inlet n:. Directly related to the power and, as is known, the burner pressure is directly related to the high pressure compressor G. t: This is because the output pressure is almost exclusively used.

The high pressure compressor stall limit value is the speed signal (N, /10
Since it is plotted in advance as a function of ζ, it is possible to set an appropriate stall margin by using the throttle limit value that corresponds to the calculated speed signal.

A stall limit signal is input to the calculator 44 via line 40, and PS+s is input via line 36.
．． The actual value of t is input manually and PS+3. , the 13B limit value for acceleration corresponds to the actual value of the stall limit signal and r'srs. It is calculated as the product of the actual value of t.

Therefore, the P■ limit value calculated here is a value independent of compressor oil, power extraction, and engine efficiency reduction, and there is no need to perform special correction to compensate for these engine conditions.

The calculated PB limit value and the actual value of Plo are input to the comparator 42, and an error signal is generated by comparing them. Based on this error signal, the fuel control device 2230 controls the fuel flow supplied to the burner 20,
A closed loop is formed here.

It is possible to use a minimum value selection gate 46, and this minimum value selection gate 46 allows the PB during steady operation to be
The smaller value of the limit value and the Pn limit value during acceleration calculated based on this embodiment is selected. This general small {/(selection gate) can be used in the specific device to which this embodiment is applied.

FIG. 2 shows a second embodiment of the invention.

1 in this example, P S in the first example,
3. , the inlet pressure P8 of the augmentor 24 is used. As a result, due to the pressure loss within the bypass duct 15, the difference between the pressure and the inlet pressure of the high-pressure compressor becomes more problematic than in the first embodiment. Therefore, in the second embodiment, means are provided to compensate for this pressure loss.

In FIG. 3, the function generator 60 has a low pressure T [
The rotational speed N. of the low pressure compressor is determined by the square root of the compressor inlet temperature divided by the standard seawater temperature (5 1 8.7 Rankine temperature). The speed signal ( N +
C t ) is manually operated. The function generator 60 has an engine pressure ratio (EP R') as a reference value in advance.
is set as a function of the speed signal (Nect), and outputs E1)R corresponding to the manually input speed signal to the calculator 64 via the line 62.

The actual value of E I) rt is entered into the calculator 64,
An error signal ΔEPR is calculated from this actual value of EPl and EPR as a reference value from line 62, and is outputted to function generator 68. Note that the actual value of EI) Il is calculated as ps (augmentor inlet pressure)/P, (low pressure compressor inlet pressure).

Also, it goes without saying that A EPR is a function of the pressure loss in the bypass duct. Function generator 6
8 has △PB/Pa set in advance as a function of △EPR, and △P II corresponding to the input △EPR.
/Ps on line 70. This △PB/P
e is a value for compensating for the pressure loss in the bypass duct, and is added to P 11 / P @ which is input manually via line 40 in FIG. 2 in adder 72. This addition-corrected Pn/ps is input to the arithmetic unit 44 shown in FIGS. 2 and 3 and processed in the same manner as in the first embodiment.

The PB limit value calculated in the first and second embodiments is the upper limit value (trim 41 (t r i m )) or topper value (t
opper)).

In this case, in a state where the acceleration rate based on dtN* is not allowed depending on the engine state, it is possible to perform transient control without causing the risk of engine stall. Incidentally, as shown in the above I and 2nd embodiments, P
B/PS+s. It goes without saying that the quickest transient control is possible when the acceleration control using t or I'B/[]6 is performed alone.

"Effects of the Invention" In the first configuration of the present invention, the ratio between the burner IE power and the predetermined engine internal pressure is used as a function as a reference value related to the speed of the compressor, and this ratio and the actual burner pressure are used as a function. Since the control signal for the burner pressure is generated by using the value and the fuel supply rI1 is controlled based on this control signal, the stall is independent from FE compressor bleed, power extraction, engine efficiency reduction, etc. Margins can be set.

[Brief explanation of the drawing]

FIG. I is a schematic diagram showing an acceleration control device for a gas turbine engine according to a first embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing a gas turbine engine according to a second embodiment of the present invention. FIG. In the figure, 10 is a twin spool axial flow fan jet engine, 12 is a fan/low positive compressor part, l4 is a low pressure turbine part, port 5 is a bypass duct, l6 is a high pressure compressor part, 18 is a high positive turbine part, 20 is a burner, 24 is an augmenter, 30 is a fuel control device, 32.60 is a function generator, 42.64 is a comparison 4, and 46 is a minimum value selection gate. Furthermore, in the second configuration of the present invention, in addition to the above-mentioned effects, pressure loss within the bypass duct is compensated for dynamically, making it possible to set an appropriate stall margin. Reisenban=Itoru

Claims (1)

[Scope of Claims] (1) A compressor, a burner for generating engine working fluid, a turbine driven by the engine working fluid to drive the compressor, and a supply to the burner according to engine operating parameters. an acceleration control device for controlling an acceleration mode of a gas turbine engine, the acceleration control device having a fuel control means for controlling a fuel flow rate of the gas turbine engine, and having a means for setting a stall margin of the compressor;
The means generate, in response to the speed of the compressor, a first signal indicative of a compressor stall limit value as a reference value, which is a ratio of the pressure in the burner and the pressure at another predetermined location of the engine. means for generating a second signal in response to an actual value of pressure in the burner; and means for generating a second signal in response to the first and second signals to limit the flow of fuel supplied to the burner. and means for controlling a control means, wherein the stall margin is independent of compressor bleed, power extraction and engine efficiency reduction. (2) Claim (1) characterized in that the engine includes a fan, a fan bypass duct for guiding fan discharge air, and an augmentor, and another predetermined position of the engine is located within the fan bypass duct. The acceleration control device described in . (3) means responsive to actual pressure in said fan bypass duct to generate a third signal; said first signal and said third signal to generate a fourth signal representing a limit value of said burner pressure; multiplication means for multiplying signals;
and means responsive to an error between the fourth signal and the actual burner pressure to further control the fuel control means. (4) The first signal is the temperature at the inlet of the compressor and 518
．． 4. The acceleration control device according to claim 3, wherein the acceleration control device is responsive to a compressor speed corrected to a reference value representing a 7° Rankine. (5) said fuel control means establishes a steady state signal that limits the value of said burner pressure, and said minimum selection means establishes a signal between said steady state signal and said fourth signal for controlling said error response means; The acceleration control device according to claim 4, wherein the minimum value is selected. (6) A high-pressure compressor and a low-pressure compressor driven by a high-pressure turbine and a low-pressure turbine, respectively, a burner for generating gas to power the high-pressure turbine and the low-pressure turbine, and the burner in a twin-spool, axial flow fan jet engine having fuel control means for regulating fuel flow to the engine, and acceleration means for controlling said engine during an accelerated mode of operation, correcting to establish a first signal; means for establishing a stall limit value as a reference value representative of a critical ratio of burner pressure to other engine operating parameters for generating a second signal;
function generating means responsive to the signal; multiplication means responsive to the actual value of the parameter and the second signal to generate a third signal representative of the burner pressure limit during the acceleration mode; and multiplication means responsive to the second signal and the burner pressure. and means for generating an error signal for controlling the fuel control means in response to the actual value of and the third signal, thereby setting a stall margin of the high pressure compressor in the acceleration mode. An acceleration control device featuring: (7) The acceleration control device according to claim 6, further comprising a bypass duct for guiding fan discharge air, and wherein the parameter is a pressure within the bypass duct. (8) the fuel control means includes means for generating a fourth signal representing a limit of the burner pressure during steady state engine operation; Acceleration control device according to claim 7, characterized in that it includes gating means responsive to a minimum value between said third signal and said fourth signal to establish an error between said third and fourth signals. (9) The accelerator according to claim 6, wherein the low pressure compressor rotor speed is corrected to a reference value calculated as a function of engine inlet temperature and 518.7° Rankine. (10) A compressor, a burner for generating engine working fluid, a turbine driven by the engine working fluid to drive the compressor, a fan, a bypass duct for guiding air discharged from the fan, and an engine. An acceleration control device for controlling an acceleration mode of a gas turbine engine, the acceleration control device having a fuel control means for controlling a fuel flow rate supplied to the burner according to an operating parameter, and a means for setting a stall margin for the compressor. has
The means generate, in response to the speed of the compressor, a first signal indicative of a compressor stall limit value as a reference value, which is a ratio of the pressure in the burner and the pressure at another predetermined location of the engine. means for generating a second signal in response to an actual value of pressure in the burner; and means for generating a second signal in response to the first and second signals to limit the flow of fuel supplied to the burner. means for controlling a control means; and means for compensating for a pressure loss in said bypass duct, said pressure loss compensating means receiving a third signal indicative of engine pressure ratio as a function of said compressor speed; and comparator means for generating a signal indicating the difference between the third signal and the actual value of the engine pressure ratio and correcting the first signal thereby. Acceleration control device for turbine engines. (11) The engine includes an augmentor, and the other station is located at an inlet of the augmentor.
).) The acceleration control device for a gas turbine engine. (1
2) means responsive to the actual pressure at the inlet of said augmentor to generate a fourth signal, said first signal and said fourth signal to generate a fifth signal representing a limit value of said burner pressure; Acceleration according to claim 11, characterized in that it includes multiplier means for multiplying and means responsive to an error between said fifth signal and actual burner pressure to further control said fuel control means. Control device. (13) The first signal is equal to the temperature at the inlet of the engine.
13. Acceleration control device according to claim 12, characterized in that it is responsive to a compressor speed corrected to a reference value representing 18.7° Rankine. (14) said fuel control means establishes a steady state signal that limits the value of said burner pressure, and said minimum selection means establishes a signal between said steady state signal and said fifth signal for controlling said error response means; The acceleration control device according to claim 13, characterized in that the minimum value is selected. (15) A high-pressure compressor and a low-pressure compressor driven by a high-pressure turbine and a low-pressure turbine, respectively, a burner for generating gas to power the high-pressure turbine and the low-pressure turbine, and the burner in a twin-spool, axial flow fan jet engine having fuel control means for regulating fuel flow to the engine, and acceleration means for controlling said engine during an accelerated mode of operation, correcting to establish a first signal; a function responsive to said first signal establishing a stall limit value as a reference value representative of a critical ratio of engine operating parameters of burner pressure to ground for generating a second signal; generating means, multiplication means responsive to the actual value of the parameter and the second signal to generate a third signal representative of the limit of the burner pressure during the acceleration mode; and multiplying means responsive to the actual value of the parameter and the second signal; means for generating an error signal for controlling the fuel control means in response to a third signal, thereby establishing a stall margin for the high pressure compressor in the acceleration mode and a corrected low pressure compressor rotor speed; in combination with bypass duct pressure loss correction means including a function generator for generating an engine pressure ratio signal as a function of the acceleration mode of the engine to generate an error signal for further controlling said fuel control means; means responsive to the actual burner pressure and the third signal to establish a stall margin for the high pressure compressor during a period between the generated engine pressure ratio and the first signal altering the actual engine pressure ratio; An acceleration control device comprising means for calculating the difference between. (16) the fuel control means includes means for generating a fourth signal representing a limit of the burner pressure during steady state engine operation; 16. Acceleration control device according to claim 15, characterized in that it includes gating means responsive to a minimum value between said third signal and said fourth signal to establish an error between them. (17) The acceleration control device according to claim 16, wherein the low pressure compressor rotor speed is corrected to a reference value calculated as a function of engine inlet temperature and 518.7° Rankine.